I’ve already checked with the manual, and I am out of ideas for now. Here’s the problem: my turn signals, air conditioning, and rear defroster do not work. I have checked all of the relevant fuses and they are all fine. The turn signal bulbs even work when I turn on the hazard lights. I have a 1991 Ford Thunderbird.
I have no idea what else it could be, but I really don’t want to take it to a shop for what is probably a minor electrical problem.
Thanks for any help.
For everything to go at once like that, you had to somehow lose an entire circuit. You’re probably right that it’s something simple. Re-check all of the fuses, not just the ones you think it is. A blown fuse is the most likely culprit, but then fuses usually blow for a reason so you might have something else going on too. Could be a bad wire, a bad ground, a corroded connector, a short caused by worn insulation, or any number of things. If it’s not a fuse then you really need someone who can trace things through and figure out where it’s gone sour.
It sounds like it could be a bad common ground.
Did they all crap out at the same time?
Can you get your hands on a schematic?
You need a friend in a garage with access to a factory schematic or a database like Mitchell On Demand. In addition to fuses, there are fusible links which are tough to find unless you know where they are in the harness.
From experience with my 1985 Ford truck, there are separate feeds for hazard and turn signal operations, and as engineer_comp_geek pointed out, a circuit doesn’t open because it feels cranky.
Thanks for the ideas everyone. Yes, I can get my hands on a good diagram of the electronics, just not right now, and yes, they did all go out at the same time.
The fusible link sounds like it might be it. Something similar went wrong with another car a while ago and it ended up being that.
You might have two sets of fuses, one under the dash and one under the hood.
Sounds like fusible link, they are often connected to the starter solenoid
I`ve got an 88 T-Bird. How do you know the rear defroster doesn’t work?
In any case I’d look at the fusible link that supplies power to the major appliances (as others have suggested).
Did you add an aftermarket alternator and/or stereo recently?
No new stereo for about 4 years, and the alternator is the stock one.
As for the defroster, the light in the switch doesn’t go on anymore. I suppose it could just be the switch that doesn’t light up, but I’m not sure, I won’t really have an opportunity to test the defroster for about 3 months.
Anyway, after looking at the diagrams in a Chilton’s manual, it does look like a bad fusible link. Is there an easy way to get to and replace it, or is it a professional job? If so, about how much would it cost?
If you want or need to test the rear defroster in the warmer months, you can apply an ice pack to the outside of the rear window for a few minutes, then turn on the defroster. Wait another minute or so for it to heat up, then gently breathe on the inside of the window under the ice pack. It’ll be pretty clear if it’s working or not.
You can replace the link yourself. Get the inline butt-splice connectors and the new fusible link at any auto parts store. You’ll need a wire cutter/stripper and a 10 gauge crimper for the butt-splices. You can get a very inexpensive tool that cuts, strips, and crimps for just a few bucks at the same place you get the link and the butt-splices.
Make sure you test the fusible link before you replace it to determine that it’s shot.
You should have voltage on both sides with the ignition on. Or you can take a continuity test across both sides of the link (with the battery disconnected), your meter should read through the link if it’s still good.